Hang onto Your Hair!

Here's your nightly math! Just 5 quick minutes of number fun for kids and parents at home. Read a cool fun fact, followed by math riddles at different levels so everyone can jump in. Your kids will love you for it.

Hang onto Your Hair!

Have you ever seen one of your own hairs on your sweater or hairbrush? We “shed” hair, meaning a few hairs fall out every day because they’re done growing. We shed between 50 and 100 head hairs each day! (Don’t worry — new hairs grow back in). Mammals all have hair, even elephants and kangaroos, and they all shed, too. So our friend Jakub J.asked, if a cat gets $1 for each hair it sheds, how rich would it be in 1 day, 1 month, and 1 year? Our furry friends have FAR more hair than we do: we have about 100,000 on our head, while a cat might have about 40 MILLION hairs on its body. If we lose 100 of our 100,000 every day, that’s 1 hair out of every thousand…so how many would that be for a cat? Let’s figure it out!

Wee ones: Hold some hair in your fingers. Now try to hold just 2 of those hairs, and let the rest go!

Little kids: Hold a hair straight up from the top of your head. About how long is it in inches? Ask a grown-up to help you guess, or use a ruler! Bonus: If you lose 50 hairs one day and 10 more then next, how many do you lose the 2nd day?

Big kids: How do you “spell” 40 million as a number? Bonus: If the cat loses 1/1000th of those hairs in a day, how many hairs is that – and how many dollars if he gets $1 for each? Then estimate for 1 month and 1 year! (Hint if needed: To divide by 1,000, you take 3 zeroes off the end of the number.)

Answers:

Wee ones: Try to pinch just 2 hairs.

Little kids: Different for everyone…it could be anywhere from half an inch to many inches. Bonus: 60 hairs.

Big kids: 40,000,000. Bonus: $40,000 in one day! In a 30-day month that cat would earn $1,200,000 (more than a million dollars), and in 12 months of about that length, it would earn $14,400,000.

About the Author

Laura Bilodeau Overdeck is founder and president of Bedtime Math Foundation. Her goal is to make math as playful for kids as it was for her when she was a child. Her mom had Laura baking before she could walk, and her dad had her using power tools at a very unsafe age, measuring lengths, widths and angles in the process. Armed with this early love of numbers, Laura went on to get a BA in astrophysics from Princeton University, and an MBA from the Wharton School of Business; she continues to star-gaze today. Laura’s other interests include her three lively children, chocolate, extreme vehicles, and Lego Mindstorms.